1. Field of the Invention
The present invention generally relates to methods of displaying a virtual world, and particularly relates to a method of displaying and manipulating a virtual world by transferring data from a remote cite to a local cite via a computer network.
2. Description of the Related Art
Development of 3D-computer-graphics technology along with enhanced processing speed of computers has made it possible to create a virtual world in computers. A world created in computers is displayed on a screen, and user operations are processed with regard to the created and displayed world, thereby establishing an interactive relationship between the users and the created world. This provides a virtual world for the users.
Further, development of computer networks has made it possible for users to enjoy various services by connecting a client device to a server device via a computer network.
An example of services provided by the displaying of a virtual world via a computer network includes a virtual shopping center. Descriptive data of a virtual world with regard to a shopping center is stored in advance in a server device, and is transferred to a client device upon a request from the client. The descriptive data of the virtual world is then displayed on a client screen. Through operations via an interface, the user can walk around in the shopping center, and can shop in virtual stores.
When a virtual world is displayed and operated via a computer network, a large amount of descriptive data of the virtual world needs to be transmitted via the network. The problem is that data transfer from the server to the client needs a lengthy period of time.
Descriptive data of a virtual world represent a shape of each object by a plurality of polygons, and includes coordinates for defining polygon shapes, normal vectors, and attributes such as polygon colors and textures. Upon a request from a user to transfer the descriptive data, a server device transfers the data to the client with respect to a large number of polygons as a single file. The client device displays the descriptive data of the virtual world after the completion of the file transfer. The user has to wait for the display and operation of the virtual world until the file transfer is finished. If descriptive data of a virtual world has a size of 100 Kbytes and is transmitted at a rate of 2400 bps, for example, the user has to wait five to six minutes before starting operation of the virtual world, which is displayed after the completion of the data transfer.
Accordingly, there is a need for a method of displaying a virtual world which can shorten the time length that a user has to wait before the virtual world is displayed in order to accept user operation.